package com.feng.mvc.controller;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.UUID;

@Controller
public class FileUpAndDownloadController {

    /**
     * 文件下载
     * 2021.11.07 20:00
     * @param session
     * @return
     * @throws Exception
     */
    @RequestMapping("/downImg")
    public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws Exception{
        //获取servletContext对象
        ServletContext servletContext = session.getServletContext();
        //获取服务器中文件的真实路径
        String realPath = servletContext.getRealPath("/static/img/R-C.jpg");
        System.out.println(realPath);
        //创建输入流
        InputStream is = new FileInputStream(realPath);
        //创建字节数组
        byte[] bytes = new byte[is.available()];
        //将流读到字节数组中
        is.read(bytes);
        //创建HttpHeaders对象设置响应头信息
        MultiValueMap<String,String> headers = new HttpHeaders();
        //设置要下载方式以及下载文件的名字
        headers.add("Content-Disposition","attachment;filename=R-C.jpg");
        //设置响应状体码
        HttpStatus statuscode = HttpStatus.OK;
        //创建ResponseEntity对象
        ResponseEntity<byte[]> responseEntity = new ResponseEntity<byte[]>(bytes,headers,statuscode);
        //关闭输入流
        is.close();
        return responseEntity;
    }

    @RequestMapping("/upFile")
    public String upFile(MultipartFile photo,HttpSession session) throws IOException {
        String filename = photo.getOriginalFilename();

        //解决重名问题，使用uuid替代名字
        String suffixName = filename.substring(filename.lastIndexOf("."));
        String uuid = UUID.randomUUID().toString();
        filename = uuid+suffixName;

        ServletContext servletContext = session.getServletContext();
        String photoPath = servletContext.getRealPath("photo");
        File file = new File(photoPath);
        if (!file.exists()){
            file.mkdir();
        }
        //file.separator: 斜线分割符（这里不确定是左还是右分割符，可以用这个语句代替）
        String finalPath = photoPath + file.separator + filename;
        photo.transferTo(new File(finalPath));
        return "success";
    }
}
